1. Field of Invention
This invention relates generally to stringed musical instruments and specifically to devices designed to harmonically, melodically or modally bend any combination of strings without changing the initial tuning of the instrument, such as guitars. It further relates to above described devices that can be easily operated by use of a remote activator such as foot pedal.
2. Description of Prior Art
Vibrato devices have been widely used for many years with stringed instruments for creating a vibrato sound which results from rapid raising or lowering of pitch during vibration of the strings. Heretofore a wide variety of devices have been proposed and implemented for this purpose.
Usually such devices are used with electric guitars and are incorporated into the guitar bridge assembly. Most vibratos require the musician to alter the tension on all of the strings of a stringed instrument simultaneously and effect pitch change during vibration of the strings.
Representative prior art embodiments include a moving tailpiece on the body of the instrument to accomplish this tension change. In such devices, a pivot point is established and the tailpiece of the assembly pivots about that point. A counter spring is typically utilized to counteract the pull of the strings on the tailpiece.
An example of this genre is disclosed in U.S. Pat. No. 4,497,236 to Rose which shows such a device for a guitar with a lever pivoting the tailpiece. Movement of the lever by the musician increases or decreases overall pitch. However, this movement of the strings as a group results in a significantly non uniform variation in individual string pitch due to the inherent and nonlinear pitch variations characteristic of guitar strings of different diameters subjected to uniform displacement.
Accordingly, use of known vibrato devices often results in a frustrating out of tune vibrato sound and string configuration because the pitch relationships within chord arrangements are often distorted. Adding to this problem is the tendency of the knife edge type string support mechanisms to dull with repeated use, which in turn make it difficult to insure accurate string return to the selected initial tuning configuration when the vibrato lever is released, resulting in an out of tune instrument.
One proposed solution to the former problem is shown in U.S. Pat. No. 3,411,394 to Jones in which a vibrato system secures the tail end of each string at different relative distances from the pivot point of the vibrato tailpiece so that the end of each string can be displaced through a greater or lesser distance relative to the other strings. Although the end of each string rotates through the same angle relative to the pivot point, this differential displacement occurs because strings positioned at a greater radial distance from the pivot point are translated over a longer distance than strings positioned at a lesser radial distance from the pivot point. However, the musician is required to use a specific string gauge at specific tuning in order for this device to function properly.
An additional problem with many of the prior art tremolos is that they support the strings in a relatively balanced or equilibrium condition when the guitar is tuned. As demonstrated in U.S. Pat. No. 4,632,005 to Steinberger, the strings attach to a single bridge plate. As a result, the total tension forces acting upon any one of the guitar strings is dependent in part upon the tension forces acting upon the remaining strings of the guitar. Therefore, adjustment in tension or breakage of any single string results in at least some alteration in the tension of the other strings. This tendency can make both the initial tuning and retuning of the strings a relatively laborious process requiring some degree of musical expertise.
In addition to the problems of maintaining pitch relationships between strings, existing patented tremolos cannot selectively alter the pitch of individual strings or combination of strings, i.e., there is no string switch ability. Nor do conventional tremolos allow the user to broadly determine the rate at which each string will be altered while maintaining the original tuning of the strings.
Furthermore, the saddle pieces of the bridge assembly, which align and guide the strings and set the intonation along the length of the strings, are, in much of the prior art, held in place by floating pins perpendicular to the string. This design allows for lateral movement of the saddle which correspondingly results in a discordant "buzz" in the string when it is vibrated resulting in unwanted noise and a loss of tonal duration. Also, there are no built in safeguards to allow the user to raise the pitch of the strings without over stressing and thus breaking a string, or means to finely control the rate the handle alters the pitch of the strings, nor mechanisms to easily lock the handle in an alternate tuning.
Finally, because most tremolos require hand manipulation of the lever attached to the bridge assembly it is often necessary for the user to break from the tempo to utilize a vibrato device through hand manipulation